Stretching machine



y 1934- R. L. GRIFFIN El AL 1,957,830

STRETCHING MACHINE Filed July so. 1931 s Sheets-Sheet 1 Wiineau' (Jzvegdfor A, M 65 B M May 8, 1934.

R. GRIFFIN ET AL 1,957,830

STRETCHING MACHINE Filed July 50, 1931 3 Sheets-Sheet 2 l iI iineuu' \K J zvgngior May 8, 1934. R. L. GRIFFIN ET AL STRETCHING MACHINE Filed July 30, 1931 3 Sheets-Sheet 3 A? IIIIIIIIIIIII A IIIIIIIIIIIIIIIL Wiineav frame,

Patented May 8, 1934 Roger L. Griffin an Mass, assignors to A. C.

TES

1,957,830 STRETCHING MACHINE d James T. ONeiLPeabody,

Lawrence Leather Company, Boston, Mass, a corporation of Maine Application July 30, 1931, Serial No. 554,024

13 Claims.

The present invention relates to stretching machines and more machines for the stretching particularly to power operated of leather hides or skins of the general type disclosed in our prior application Serial No. 521,931

, filed. March 12,

The object of the present invention is to simplify and improve machinery particularly the machine of s tion.

With this and other objects of this type and aid prior applicain view, as will be apparent to those skilled in the art, the present invention consists of the devices, combinations and arrangement of parts hereinafter described j and claimed.

The invention in its prefer trated in the accompanying red form is illusdrawings in which Fig. 1 is a top plan View of the stretching machine with the top or table removed; Fig. 2 is a j side elevation of the stretching machine showing the stretching mechanisms;

Fig. 3 is an end elevation of the stretching machine; Fig. 4 is a detail view of a part of the oper Fig. 5 is an end view of the me 7 Fig. 4; and Fig.

a stretching mechanism on lin 6 is a sectional view ating mechanism; chanism shown in in section of e 66 of Fig. 4.

The illustrated embodiment of the invention comprises a removable, expansible frame having side pieces 8 and overlying end in dot-and-dash lines in the pieces 10, shown drawings, and of construction similar to that shown in the copending application above referred to. The

be stretched, is secured skin or other material to hide by toggles or in any other suitable manner to the then expanded to stretch the orting legs 12 carfor supporting a ewhat smaller distretching frame.

affords a support for the hide which it is being toggled'to the The hide being now attached to the expansible the frame is expanded by means of four pairs of substantially vertical pivoted arms or levers. side pieces 8 of the expansible at 18 and the two pairs at 20. Each arm 18 is pivoted naled in bearings 22 at the lower ends of and 24 carried brackets 26 and 28 attached The two pairs of arms for acting on the frame are shown of arms for acting on the overlying end pieces 10 of the frame are indicated on a stud 21 jourrespectively to the legs and frame of the machine. At its upper end, each arm 18 is provi ded with an outwardly facing dog 30 to engage internally the side piece 8 of the expansible frame. Extending outwardly from each arm is a ledge 32 on which the side piece8 is supported. Each side piece 8 is supported on the ledges 32 of a pair of the arms 18.

The arms 20 for expanding the end pieces 10 are provided at their upper ends with dogs 34. Inasmuch as the end pieces 10 of the frame are supported by the side pieces 8, the arms are not required to be supplied with any supporting means similar to the ledges 32.

Each arm 30 and 34 is provided at the top with a small overhanging hook 36 which, upon expansion of the frame, overlies the corresponding side or end piece thereof and prevents accidental upward movement of the frame.

Connected between adjacent brackets 28 on each of the four sides of the machine is a tray 39 which not only imparts rigidity to the machine, but also affords a convenient receptacle for toggles and clasps.

The end pieces 10 of the frame are expanded simultaneously by a single motor 40. The side pieces 8 are expanded by means of two motors 42 and 44, one being adapted to actuate the arms 18 at the neck end of the hide and the other to actuate the arms 18 at the butt end of the hide. The longitudinal stretch brought about by the motor 40 is therefore uniform throughout the width of the hide, but the lateral stretches, which in most cases should be different for the neck andbutt ends, are under the independent control of the motors 42 and 44.

Since the operating connections for the several motors are similar, the connections for the motor 44 only will be described in detail. This motor is connected to opposite arms 18 at one end of the machine in the following manner:- In Fig. 1, the motor shaft 46 is connected through couplings 48 with reducing gearing indicated generally at 50. Extending from each side of the reducing gear box is a shaft 52 carrying at each end a hollow rotatable member 54 which is removably secured to a rotatable nut 56 by pins 58. The member 54 and the nut 56 are journaled in bushings 60 and 62 secured in a split journal 64. As shown in Figs. 4 and 5, the journal 64 comprises a part 66 attached to the frame of the machine and a part 63 which is secured to the part 66 by bolts '70. The parts 66 and 68 enclose the bushings 62 and 60 as well as an end thrust bearing 72. The two parts of the journal are provided at opposite sides with longitudinal slots '74 to slidingly accommodate a pin 76 forming which engage the end formed on the end of a screw which threads into the nut 56 and projects beyond the nut into the hollow part of the rotatable member 54. A link 82 connects the pin 76 with the side stretching arm 18. The same construction is used on opposite sides of the gear box 50. Similar connections are provided leading from the motor 42 to the opposite arms 13 at the other end of the machine.

On the shaft 52 is mounted a sprocket 84 connected by the chain 88 with a limit switch indicated generally at 90 to stop the motor at the limit of the extreme expansion or contraction of the frame. A limit switch 91 of similar construction is provided for the shaft driven by the motor 42.

The motor 40 which produces the uniform longitudinal stretch, is provided with a single shaft 92 connected at opposite ends with the reducing gear boxes 33, each of which operates through exactly the same connections as described above for moving the opposed arms 20 pieces 10 of the expansible frame.

In stretching a hide, as explained in the copending application above referred to, it has been found that while different degrees of lateral side stretch are usually desirable at the shoulders and butts, the longitudinal or lengthwise stretch should be substantially uniform. Accordingly, a uniform longitudinal stretch is produced by the single motor 40 and the lateral stretches are independently produced at opposite ends by the motors 42 and The electrical connections are similar to those disclosed in the co-pending application, and are not shown in detail here. During the stretching operation, the motors are under the control of the operator. When the desired limit of stretching has been reached, the frame is locked in its expanded position and then the motors all operate in the reverse direction to restore the arms to their initial position, the extent of movement of the arms being controlled by the limit switches.

In operation, the expansible frame is ordinarily mounted in contracted condition upon the stretching machine with its levers in the initial or retracted positions, and the hide is spread out upon the stretching machine top and toggled to the frame by means of the toggles and their attaching cords. The provision for toggling by working on the machine top forms an advantage over the construction of our co-pending application in that it avoids preliminary handling and transporting of toggled hides. However, if desired, the hide may be toggled on the frame and moved to the machine.

The operator then sets in forward motion by a common forward control all of the stretching levers which move outwardly simultaneously and uniformly to exert a preliminary stretching of the hide. When sulhcient preliminary stretching has been imparted, the common forward control is then released, and the other proper controls are actuated to stretch the hide lengthwise, or transversely at the neck or at the butt as may be required. These differential stretchings may be effected concurrently or consecutively, as the operator desires, and in the direction and amount as the operator in his judgment shall deem advisable, until the hide is properly stretched.

The controls are then released, and the hide is held under tension by the stretching levers. The stretching frame is then looked at its four corners 1,957,830 part of a cross-head 78. The cross-head 78 is in the expanded condition. The common reverse control is then actuated and the stretching levers automatically return to their initial positions. With the contraction of the stretching arms, the stretching frame and its hide may be removed from the machine for drying or other treatment. Thus, a hide may be stretched by power operated stretching devices in an expeditious and exact manner under the full control and judgment of the operator according to the character of the hide, its intended use, etc.

It will be noted that the motor shafts and the parts directly driven thereby are subjected only to rotative movements along the motor axes, so that the use of universal joints is avoided. More'- over, the only motions of parts beyond the machine frame are the relatively slow movements of the stretching arms and the operating links, all rotating and rapidly moving parts being safely confined within the machine.

While the present invention has been shown and described as embodied in a machine for stretching hides, it is understood that it is not necessarily limited thereto but may be embodied in machines for stretching other materials. Nor is the present invention to be limited to the particular form and arrangements herein shown and described, but it may be embodied in other and different forms and combinations within the language of the claims.

Having thus described the invention, what is claimed is:

1. A stretching machine for an expansible stretching frame having, in combination, pivoted stretching arms movable in planes transverse to the plane of movement of the expansible frame, a motor, a threaded nut rotated by the motor, a screw movable longitudinally through the nut, and means for transmitting movement of the screw to a stretching arm, said means having provision for preventing rotation of the screw.

2. A stretching machine having, in combination, a table comprising a top and a supporting frame, pivoted stretching arms carried by the frame and positioned beyond the margin of the top, means positioned beneath the table top for actuating the arms, said means comprising a journal secured to the frame, a nut rotatable in the journal, and a screw movable longitudinally through the nut, and a linlr connecting the screw and the stretching arm.

3. A stretching machine having, in combination, a frame, a pivoted stretching arm, a journal secured to the frame, a nut rotatable in the journal, a screw movable longitudinally through the nut, a cross head on the screw including a pivit pin, the journal having slots to permit longitudinal movement of the pivot pin and to prevent rotation of the screw, and a link connected between the pivot pin and the stretching arm.

4.. A stretching machine having, in combination, a machine frame, a plurality of stretching arms to engage an expansible frame near the corners thereof, brackets attached to the machine frame, means for pivoting the arms in the brackets, and bracing means connected between adjacent brackets on each side of the machine.

5. A stretching machine having, in combination, a machine frame, a plurality of stretching to engage an expansible frame near the corners thereof, brackets attached to the machine frame, means for pivoting the arms in the brackets, and bracing means connected between adjacent brackets on each side of the machine, said bracing means comprising trays underlying the expansible frame.

6. A stretching machine for an expansible stretching frame having, in combination, a plurality of pairs of opposed pivoted stretching arms movable in planes transverse to the plane of movement of the expansible frame, and means for actuating each pair of arms, said means comprising a pair of oppositely threaded screws, driving mechanism therefor, and links between the screws and the arms, the links, screws and mechanism all being positioned and operating in a substantially straight line.

'7. A stretching machine for an expansible stretching frame having, in combination, a supporting frame, stretching arms pivoted adjacent the bottom of the supporting frame and extending thereabove to engage and expand the stretching frame, and means beneath the top of the supporting frame for actuating the arms, said means comprising a motor, a threaded nut rotated by the motor, a screw movable longitudinally through the nut, and means transmitting movement of the screw to the stretching arm.

8. A stretching machine for an expansible stretching frame, having, in combination, a supporting frame, arms pivoted on the supporting frame to move in planes at right angles to the plane of movement of the expansible frame and means for actuating the arms, said means comprising a motor, reduction gearing connected therewith, a pair of cooperating threaded members, straight line drive connections between the gearing and one of said members, and a link operating substantially in the line of said drive for connecting the other of said members and one of said arms 9. A stretching machine having, in combination, a plurality of stretching arms for engaging and expanding an expansible stretching frame, said arms being pivotally mounted to move in planes transverse to the plane of the frame while expanding the frame, a separate set of actuating means for each arm, each set comprising a rotatable threaded nut, a screw movable longitudinally therethrough, a cross-head carried by the screw,

and a link pivotally connected at one end to the cross-head and at the other to a stretching arm, and means for rotating the threaded nuts.

10. A stretching machine having, in combination, a stationary framework, a plurality of vertical stretching arms pivotally mounted at one end of the framework and having an outwardly facing dog at the other end to engage an expansible stretching frame, means for actuating the arms in planes transverse to the plane of the frame, and an overlying, hold-down hook on the dog to prevent upward movement of the frame during the expanding movement thereof.

11. A stretching machine having, in combination, a plurality of substantially vertical, outwardly faced, pivotally mounted stretching arms to engage and support the members of an expansible stretching frame at points adjacent the corners thereof, the frame intermediate said points being free and unsupported, and a horizontal table disposed inwardly of the arms and of smaller dimensions than the expansible frame to support the material to be stretched during attachment thereof to the frame and while the latter is supported by the arms.

12. A stretching machine having, in combination, a plurality of pivotally mounted stretching arms for expanding a stretching frame, means for actuating the arms comprising an internally threaded nut mounted to rotate in a fixed bearing, a screw in the nut, a cross-head carried by the screw, a link connecting the cross-head and one of the stretching arms, and a supplementary thrust bearing for the nut.

13. A stretching frame having, in combination, a plurality of pivotally mounted stretching arms for expanding a stretching frame, means for actuating the arms comprising a rotatable internally threaded nut, a bearing member for the nut provided with a guideway, a screw in the nut, a cross-head carried by slide in the guideway, and a link connecting the cross-head and one of the stretching arms.

ROGER L. GRIFFIN. JAMES T. ONEIL.

the screw and mounted to 

